<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<script>
  const nums = [10,20,111,222,444,40,50];

  let newsNums = nums.filter(function(n){
    return n<100;
  });

  console.log(newsNums);

  newsNums = newsNums.map(function(n){
    return n * 2;
  });

  console.log(newsNums);

  newsNums = newsNums.reduce(function(preValue, n){
    return preValue + n;
  },0);

  console.log(newsNums);
</script>
</body>
</html>